Photooxidation of Guaiacol to Organic Acids with Hydrogen Peroxide by Microwave Discharge Electrodeless Lamps

2015 ◽  
Vol 39 (1) ◽  
pp. 97-101 ◽  
Author(s):  
Dajie Zhang ◽  
Binzhe Sun ◽  
Lian Duan ◽  
Yufang Tao ◽  
Aihua Xu ◽  
...  
2019 ◽  
Vol 64 (5) ◽  
pp. 222-224
Author(s):  
S. N. Andreev ◽  
L. M. Apasheva ◽  
M. Kh. Ashurov ◽  
N. A. Lukina ◽  
B. Sapaev ◽  
...  

1931 ◽  
Vol 4 (1) ◽  
pp. 35-38 ◽  
Author(s):  
W. H. Hatcher ◽  
M. G. Sturrock

Preliminary results obtained by measuring changes in conductivity of organic acids mixed with aqueous hydrogen peroxide show a rapid though measurable progression to the attainment of a maximum or minimum within an hour. These establish previous findings, and afford a clue to the conductivity of organic peracids.


2003 ◽  
Vol 39 (11) ◽  
Author(s):  
Durelle T. Scott ◽  
Robert L. Runkel ◽  
Diane M. McKnight ◽  
Bettina M. Voelker ◽  
Briant A. Kimball ◽  
...  

1975 ◽  
Vol 53 (16) ◽  
pp. 2490-2497 ◽  
Author(s):  
José L. Arnau ◽  
Paul A. Giguère

The kinetics of oxygen evolution on warming the trapped products (at −196 °C) from water or hydrogen peroxide vapor dissociated in a glow discharge were studied by the manometric method. Under closely controlled conditions it was possible to distinguish clearly the decomposition of the two intermediates, H2O3 and H2O4. The latter begins to decompose measurably following crystallization of the glassy solid at about −115°; the trioxide decomposes readily between −50 and −35°. Typically, the yields of H2O3 from dissociated water vapor were of the order of 3 to 5 mol%; those of H2O4, only about one-tenth as much. Varying the distance between the microwave discharge and the cold trap was found to affect differently the yields of the various products. Those of water and peroxide showed a simple, direct correlation; the minor constituents H2O3 and H2O4 followed entirely different patterns. Only a small fraction of the peroxide is formed via the H2O4 intermediate in these systems. Less water, and more of the higher oxides, were obtained from dissociated hydrogen peroxide than from water vapor.The deuterated systems showed some unusual isotope effects. The yields of D2O3 were always higher (up to twice and even more) than those of H2O3 under similar conditions. The other products showed little or no such effect, except for occluded oxygen and ozone which decreased by about half. Finally, the deuterium polyoxides decompose at slightly higher temperatures (10 to 15°) than their hydrogen analogs. Mechanisms are proposed for the formation and decomposition of the polyoxides.


SCISCITATIO ◽  
2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Nur Khikmah ◽  
Nunung Sulistyani

Bakteri Asam Laktat (BAL) yang terkandung dalam susu fermentasi akan menghasilkan asam-asam organik, hidrogen peroksida, diasetil, asetaldehid, asetoin, reutinin, reuterisiklin dan bakteriosin, dapat sebagai anti-Candida. Spesies Candida non-albicans seperti C. tropicalis dan C. glabrata sebagai penyebab kandidiasis oral cenderung meningkat. Tujuan penelitian ini mengetahui aktivitas antifungi susu fermentasi komersial pada Candida non-albicans dan viabilitas bakteri asam laktat di dalam susu fermentasi komersial. Aktivitas antifungi pada Candida non-albicans dilakukan dengan metode difusi sumuran. Viabilitas bakteri asam laktat dihitung berdasarkan jumlah bakteri asam laktat sebagai jumlah bakteri total (Total Plate Count). Hasil penelitian menunjukkan bahwa susu fermentasi komersial lebih mampu menghambat C. tropicalis dibandingkan C. glabrata. Viabilitas bakteri asam laktat dalam susu fermentasi komersial 107-1010 CFU/mL. Lactic Acid Bacteria (LAB) contained in fermented milk will produce organic acids, hydrogen peroxide, diacetyl, acetaldehyde, acetoin, reutinin, reuterycline and bacteriocin, as anti-Candida. Candida non-albicans species such as C. tropicalis and C. glabrata as causes of oral candidiasis tend to increase. The aim of this research was to determine the antifungal activity of commercial fermented milk against Candida non-albicans and viability of lactic acid bacteria in commercial ermented milk. The antifungal activity was determined using well diffusion method. Viability of lactic acid bacteria is calculated as Total Plate Count. The results showed that commercial fermented milk was more able to inhibit C. tropicalis compared C. glabrata. Viability of lactic acid bacteria 107-1010 CFU/mL.


1998 ◽  
Vol 64 (1) ◽  
pp. 68-73 ◽  
Author(s):  
Ulises Urzúa ◽  
Philip J. Kersten ◽  
Rafael Vicuña

ABSTRACT The ligninolytic system of the basidiomycete Ceriporiopsis subvermispora is composed of manganese peroxidase (MnP) and laccase. In this work, the source of extracellular hydrogen peroxide required for MnP activity was investigated. Our attention was focused on the possibility that hydrogen peroxide might be generated by MnP itself through the oxidation of organic acids secreted by the fungus. Both oxalate and glyoxylate were found in the extracellular fluid ofC. subvermispora cultures grown in chemically defined media, where MnP is also secreted. The in vivo oxidation of oxalate was measured; 14CO2 evolution was monitored after addition of exogenous [14C]oxalate to cultures at constant specific activity. In standard cultures, evolution of CO2 from oxalate was maximal at day 6, although the MnP titers were highest at day 12, the oxalate concentration was maximal (2.5 mM) at day 10, and the glyoxylate concentration was maximal (0.24 mM) at day 5. However, in cultures containing low nitrogen levels, in which the pH is more stable, a better correlation between MnP titers and mineralization of oxalate was observed. Both MnP activity and oxidation of [14C]oxalate were negligible in cultures lacking Mn(II). In vitro assays confirmed that Mn(II)-dependent oxidation of [14C]oxalate by MnP occurs and that this reaction is stimulated by glyoxylate at the concentrations found in cultures. In addition, both organic acids supported phenol red oxidation by MnP without added hydrogen peroxide, and glyoxylate was more reactive than oxalate in this reaction. Based on these results, a model is proposed for the extracellular production of hydrogen peroxide by C. subvermispora.


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